Using Space Lasers to Measure Atmospheric Carbon Dioxide

By 2016, we just might have space lasers measuring the carbon dioxide in the atmosphere, and telling us whether or not (or how quickly and for how long) we’re melting the planet.

The Advanced Space Carbon and Climate Observation of Planet Earth – or A-SCOPE for short – is one of six possible missions to be considered for a feasibility study, which could lead to a 2016 launch timeframe for the mission. The idea is to understand more about how carbon dioxide moves between atmosphere, land and ocean in order to improve how we calculate the impact the greenhouse gas has on the earth, and therefore improve estimates on what we can do about it. In order to accomplish this, the project aims to do something really interesting:

The proposed measuring technique involves two short laser pulses being emitted at two adjacent wavelengths. This results in carbon dioxide being absorbed at one of the wavelengths but not by the other, which serves as a reference. The comparison of the reflected signals from both wavelengths yields the total column concentration of carbon dioxide. This novel approach implies that the return signal depends on the reflectance properties of the area of ground illuminated by the laser.

There is still a lot of footwork to do for this project, but if it is chosen, it could represent a very Star Trek way of analyzing carbon dioxide on earth - though it could be too little too late. The work they’re doing also is expected to help out scientists working on laser technology in general.

Other Earth Explorer future missions under consideration include BIOMASS - to take global measurements of forest biomass; CoReH2O - to make detailed observations of key snow, ice and water cycle characteristics; FLEX - to observe global photosynthesis through the measurement of fluorescence; PREMIER - to understand atmospheric processes linking trace gases, radiation, chemistry and climate; and TRAQ - to monitor air quality and long-range transport of air pollutants.